Jul 15, 2003

I’ve added another feature to my little experiment from yesterday:
When you click this link,
you will
be able to see the realtime noise level values outside of my office, and (if you have
Apple’s Quicktime multimedia software installed
on your computer) you will be able to hear what you are measuring - all
from the comfort of your home or office.

Now I’m not going to pretend I’m the first to do this - I think airport noise monitoring
systems have been doing similar feats for years. But this a noise monitoring system
that complies with ANSI Type 1 noise regulations, and can log 1/3, 1/6 and 1/12 octave bands
for about $4,000 (hardware and software included, network connection extra) - that’s
about the price most vendors charge for a Type 1 handheld SLM with 1/3 octave band capability.
It’s an example of what we can achieve if we take advantage of commodity hardware.

FYI, the audio is streaming at a 16kHz sampling frequency do conserve bandwidth.
However, I believe the system could easily handle several connections at 44.1 kHz sampling
rate (CD quality) with no significant degradation - and this is on 3 year-old hardware.

Update: Really silly bug - pressing the “Reset” button will reset the
LMax, LMin, LEQ, minute and second values, but not
the hour value. The bug is already fixed, but I won’t have a chance to update the server
software until Friday.